1. Field of the Invention
This invention relates to a method and apparatus for encoding/decoding image data. It is particularly applicable to the encoding/decoding of images that can be separated into their constituent parts as may be used in composite picture systems used in law enforcement, artistic creations, recreation and education.
2. Background
It is known in the art to create images on the basis of components that are assembled to form a complete image. For example, a common technique for synthesizing single images of faces involves horizontally dividing the image of a face into bands for different features of the face such as hair, eyes, nose, mouth, and chin, respectively. Paper strips containing exemplary features are then be combined to form a composite drawing of a face. Yet another example involves a program element running on a computing platform which allows a user to select individual components and combining them on a pre-selected face. In a typical interaction, the user first selects the shape of the face then eyes, nose, mouth and other components and combines them to form a facial image. Many variations on this theme can be used as described in Kakiyama et al. U.S. Pat. No. 5,600,767, Yoshino et al. U.S. Pat. No. 5,644,690, Sato et al. U.S. Pat. No. 5,537,662 and Belfer et al. U.S. Pat. No. 5,649,096 whose contents are hereby incorporated by reference. For example, the Sato et al. Patent, entitled Electronic Montage composing apparatus, describes a system for creating a montage image of a face using a plurality of basic parts stored in a library.
In constructing an image, pictorial entities are selected from a library of pictorial entities as assembled into images. These images may then be stored on a computer readable medium commonly referred to as a database or repository. Often, the storage of an image requires significant amounts of memory, often necessitating Large repositories. For example, a composite picture system used in a police department often requires maintaining records of thousands of individuals. The images are typically stored in files in some graphical format such as a “bitmap”, “gif” or “jpeg” are other format. Although such encoding schemes provide a compressed representation of the image, the memory required for storing the image remains significant. In addition, compression methods of the type described above generally degrade the quality of the image. The size and quality of images is also particularly significant when the images are transmitted from one site to another via a digital link. For example, a given police station may transmit a composite picture to another police station in order to share information about a given suspect.
Thus, there exists a need in the industry to refine the process of encoding images such as to reduce the memory requirements for storage and the bandwidth required for the transmission of the image.